Re: COIL FORM FOR MONSTER BL COIL

To: tesla-at-pupman-dot-com
Subject: Re: COIL FORM FOR MONSTER BL COIL
From: "Robert W. Stephens" <rwstephens-at-headwaters-dot-com> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Tue, 22 Sep 1998 12:38:06 -0600
Approved: terryf-at-verinet-dot-com
Tesla List wrote:
> 
> Original Poster: Cabbott Sanders <cabbott-at-cyberis-dot-net>
> 
>  For those of you who dont know, i am building a 24"d.x84" tall secondary
out
> of #10 wire. I have all the parts i need exept the coil form.   I have an
idea
> on how to make the coil form.  here it is:
> 
> I could buy (12) 12' lengths of 2x2 lumber, and arrange them circularly
into a
> 24" diameter 10 foot tall tube (I saw an image of tesla's that looked
similar)
> 
> To hold them together, i'll take 4 plywood circles (two on top, two on
bottom)
> with cut-outs for each 2x2 to fit nicely in a circle 24" od.
> 
> I would heat up the wood strips to get all the moisture out.  Then I'd get a
> BUNCH of paraffin wax, heat it up with an iron and drip it on the wood frame
> sections. I'd iron it on all the wood to make it adhere and soak in. This
> should protect the sections from moisture.  I could also coat the top and
> bottom circular plywood sections.  Moisture would not be absorbed into the
> wood, but would rather just collect on it and drip to the floor (if it ever
> got
> that moist) and evaporate.
> 
> After the "tube" is complete and all assembled together (finishing nails?
wood
> glue?) i would slide the center onto a large metal pole which i have, and
> up on
> to saw horses for winding the #10 wire.  It might take two people to hand
wind
> the 159 lbs of #10... i cant wait!  With that in mind, i'd want this coil
form
> to be awfully sturdy!!
> 
> If anyone has ever tried this method, please respond!!  I think it would
work,
> but i've never tried it.  Does anyone know Tesla's phone number??
> 
> I am looking into renting a barn or shed that doesnt leak water.  My current
> lab has i leak that i just found out about... Cause it leaked right down
on my
> brand new (30 degree inverted cone) primary!! all the (now drenched) wood
> supports  were made of particleboard.  i fired up the coil but it was no
use!
> my primary was a maraid of sparks and ground discharges!
> 
> Consistent Coiling,
> 
> Cabbott (Coil bot) Sanders

Cabbott,

You describe an almost identical assembly technique to that which I
employed to wind a fairly large resonator consisting of 4 plywood discs
28 inches in diameter and 8 pieces of 2 inch OD ABS water pipe as
vertical supports spaced evenly around the disks.  I drilled holes
through the pipe through which I drove brass woodscrews into to hold the
pipes to the plywood disks.  In the middle of the inner two discs I cut
a tight interference hole with a jigsaw through which slid and now
lives, a 6 inch PVC pipe as a central column to give the unit some extra
strength.  Metal L-brackets hold the ends of the central tube to the
inside of the two end discs. The plywood merely received several coats
of marine polyurethane enamel.  The entire resonator is close wound with
#12 HTTN plastic coated stranded wire (~4200 feet) wound to a length of
67-1/2 inches and has a diameter of 30 inches between flats. It has
produced discharges 3+X it's coil length (18 feet) without self
breakdown.

I'd use this technique again but would cut out little half round indexes
for the vertical pipes to seat (nice idea).

I've had no leakage problems with the black ABS pipe I employed but
would suggest, as in any HV application, testing the proposed plastic
for leakage losses first before committing it to your project.

If you do some searching you may find straight sided polyethylene
plastic barrels which are 24 inches in diameter.  If you 'weld' these
together with a large soldering iron you will have a virtually lossless
coilform that does not absorb moisture.

Good luck,

Robert W. Stephens